Centering device for logs



April 7, 1970 G. DON 3,504,719

' CENTERING DEVICE FOR LOGS Filed March 22, 1967 2 Sheets-Sheet 1 HT7OR VE KS April 7, 1970 G. DON 3,504,719

CENTERING DEVICE FOR LOGS Filed March 22, 1967 2 Sheets-Sheet 2 u //v VENTOR Gu/wwfi? DON A TTOAA/EYS United States Patent US. Cl. 144-209 8 Claims ABSTRACT OF THE DISCLOSURE A device for centering logs to be moved into wood peeling machines, the device having tong-like centering levers for actuating controls for movement of the lifting devices.

The present invention relates to a centering device for logs which are to be worked in wood peeling machines or the like having two lifting devices spaced apart from and independent of each other, each of which supports the log at two points and with each of which there is associated a feeling device for determining the center of the cross section of the log.

In the known centering devices of the above-mentioned type, feelers which are kinematically connected with the lifting devices for the logs are used, and in this case the feelers carry out movements which are in opposite direction to the movements of the lifting devices. Such an arrangement has not been satisfactory, since it is bound to the machine and does not permit a clear and unequivocal separation between the elements of the lifting device which are normally sturdy and heavy and the centering elements which are to operate with delicate sensitivity.

The object of the present invention is to develop a centering device which does not have the above-indicated drawbacks, i.e., in particular, is not part of the lifting devices but forms an independent measuring unit. This objective is achieved by the fact that each feeler device has two interconnected feeler arms arranged in the manner of tongs.

The centering device in accordance with the invention affords the advantage that it represents an independent structural group which can be used with centering devices of the most varied construction and which permits building-block construction. Furthermore, one obtains a clear separation between the part of the device which moves the log and the part which effects the measurements.

In addition to this, the device in accordance with the invention creates the prerequisites for the log not only to be automatically centered as heretofore in a vertical plane, but also for automatic centering in a horizontal direction to be possible, since the feeler members are independent of the lifting device. In order to make such centering possible, it is furthermore proposed in accordance with the invention that the feeling devices be so arranged that they are swingable about a common axis. The swinging action can be affected, for instance, by a hydraulic motor. As shown by experience, the utilization made of the log upon centering in the two or even more planes is substantially greater than with centering in only one plane.

In order to permit the feeler arms to act at a favorable point on the log, they are displaceable in the direction of their common axis of rotation. The amount of the displacement in the direction toward the common axis of rotation is in this connection advantageously limited by a stop which comes against the front end of the log. In order to assure simultaneous movement of both feeler arms of each pair of feeler arms, the feeler arms are connected with each other by gears.

"ice

advisable that at least one feeler arm of each pair of feeler arms consists of two parts connected with each other by a swivel, one of which, as part developed as a feeler, can shift its position with respect to the other by amounts which are limited by stops. Such an arrangement makes it possible to reduce the speed of advance of the members which displace the log vertically and/or horizontally, over a given distance during the last phase of the centering.

Further details and features of the invention will be apparent from the following description in which one illustrative embodiment of the invention is explained in further detail.

In the drawings:

FIG. 1 is a front view of a centering device in accordance with the invention;

FIG.'2 is a side view of the centering device in accordance with FIG. 1; and

FIG. 3 shows a detail of the invention indicated at A in FIG. 1.

In FIG. 1, 11 is the log which is supported on two prismatic supports 12, 13 which are carried by the piston rods 14, 15 of two lift cylinders 16, 17. The lift cylinders are arranged at carriages 18 which are movable horizontally by lift cylinders 19 on guides 20, 21.

On both sides of the log there are arranged centering devices of the same construction. The centering devices consist essentially of a first feeler arm 23 consisting of a single part and of a second feeler arm 24 consisting of two parts.

The feeler arms are rotatably supported on pins 25 and 26 and connected with each other by gear segments 27 and 28. The pins 25 and 26 are supported by side plates 29 and 30 which are seated on a sleeve 31 which is guided by a rod 32. By the hydraulic motor 34, the sleeve can be moved, together with the supporting arms, in the direction of the pin 35. Furthermore, it is possible to swing the supporting arms around the pin 35. The swinging movement is introduced by the hydraulic motor 36 which acts on a bushing 37 which is connected for rotation via the hydraulic motor 34 with the sleeve 31 and the supporting arms 23, 24.

The rod 32 is supported for rotation and displacement in the bushing 37, while the bushing 37 is arranged swingably in the bearing 38. The bearing 38, in its turn, is borne by a stand 39 to which the hydraulic motor 36 is also fastened.

The connection of the piston 40 of hydraulic motor 36 to the bushing 37 can best be seen in FIG. 2.

As can be noted in FIG. 1, the feelers 41 of the feeler arms 24 which additionally are provided with feeler rollers 42 at their ends in the same way as the other feeler arms assume two positions, namely, a first position of rest shown in solid line and a second end position shown in dashed lines. A spring 43 holds the feeler 41 in its position of rest in which it comes against the stop. A stop 45 limits the end position of the feeler 41.

The details of the limiting of the position of the feeler 41 can be seen in FIG. 3. As shown therein, the second part 46 of the swing lever 24 is provided with two extensions 47 and 48 which bear the stops 44 and 45, respectively. It also has a bridge 49 with two switches 50 and 51. These switches 50 and 51 cooperate with a gib 52 which is fastened to the feeler 41 and can actuate at one time only one of the two switches 50 and 51.

The centering device in accordance with the invention operates as follows:

In order precisely to determine the central axis of the log 11, a centering in the vertical direction is first effected. For this purpose, the log is first of all transferred from a supply bench 53 (FIG. 2) onto the prismatic support 12 of the supporting device. Thereupon the supporting arms 23, 24 are moved from the side over the log. Their measurement position is determined by the stop 33 which can be adjustable. When the feeler arms 23, 24 have reached their measuring position, the cylinder 54 is actuated and the feeler arms, due to the fact that they are connected by the gearing 27, 28, are moved uniformly toward each other. The feeler 41 is in this connection in the position shown in solid line. As soon as the feeler arm 23 rests against the bottom of the log, the lift cylinder 17 associated with it can lift the log further. The lower feeler arm follows along and at the same time the feeler 41 approaches the log from above. When the feeler roller 42 of the feeler 41 strikes against the log, the feeler is brought from the position shown in solid line into the position shown in dashed line, overcoming the force of the spring 43. In this connection, the switches 50 and 51 are actuated, the gib 52 first releasing the switch 50 which acts on the feed circuit for the lift cylinders 16, 17 and reducing their speed of advance. The log 11 is now moved in slow speeed further upward until the feeler 41 has reached its end position. At the moment that it reaches its end position, the gib 52 actuates the switch 51 and disconnects the lift devices. The log is centered in the vertical direction.

Thereupon the feeler fork formed by the feeler arms 23 and 24 is again opened by a certain amount and the feeler devices swung 90 by means of the cylinder 36 in order to be able to effect a centering in the horizontal plane. The centering process in the horizontal plane is effected in the same manner as the centering process in the vertical plane.

Of course, it is possible to vary the device of the invention within the scope of the inventive concept. Thus, for instance, the switches 50 and 51 could be replaced by a similar signal transmitting means which controls the closing of a control slide which reduces the advance of the vertical and/or horizontal cylinder from a given initial value continuously to zero.

What is claimed is:

1. In a log peeling machine including log lifting means, the combination of spaced feeler means engageable with a log supported on said lifting means for predetermining the vertical position of said log preliminary to peeling thereof, said feeler means controlling the movement of said lifting means, and said feeler means including at least two pairs of tong-like interconnected feeler arms engageable with spaced points on the log and being rotatable about the longitudinal axis of and whereby the log is centerable in different planes for peeling.

2. A device according to claim 1 wherein there are two independent spaced lifting means, each having a feeler means thereon for controlling the same.

3. A device according to claim 1 wherein the feeler means are movable toward the ends of the log until stop means is actuated by the ends of the log.

4. A device according to claim 1 wherein the feeler arms are coupled together by a gear drive.

5. A device according to claim 2 wherein said log lifting means have hydraulic means for displacement thereof.

6. A device according to claim 2 wherein the feeler arms are connected to step actuated switch means for first reducing speed of the lifting means and then stopping the same after a predetermined further advance.

7. A device according to claim 2 wherein one of the feeler arms of each pair is composed of two levers pivotally mounted relative to each other.

8. A device according to claim 7 wherein the two levers have spring means therebetween.

References Cited UNITED STATES PATENTS 1,646,115 10/1927 Sjostrom. 2,839,106 6/ 1958 Mueller l44209 X FOREIGN PATENTS 212,556 12/1960 Austria. 1,162,539 2/1964 Germany. 1,195,932 7/ 1965 Germany.

DONALD S. SCHRAN, Primary Examiner US. Cl. X.R. 822.5, 

